Difference Between C3 and C4 Plants

The main difference between C₃ and C₄ plants is in their leaf anatomy and carbon fixation pathways. C₃ plants have more mesophyll cells and use the Calvin cycle, while C₄ plants have two mesophyll cells, possess Kranz anatomy, and use the C₄ pathway for carbon fixation. Additionally, C₃ plants are more widespread (about 95% of plants), whereas C₄ plants constitute a smaller proportion (around 5%).

C₃ vs. C₄ Plants

Here are the main Difference Between C₃ and C₄ Plants:

Factors	C3 Plants	C4 Plants
Photosynthetic Pathway	C3 photosynthetic pathway	C4 photosynthetic pathway
Leaf Structure	Simple leaf structure	Specialized leaf structure
CO2 Fixation	Direct fixation in mesophyll cells	Initial fixation in mesophyll cells and then in bundle sheath cells
CO2 Concentration	Lower concentration in leaf tissues	Higher concentration in leaf tissues
Efficiency	Less efficient in hot and dry conditions	More efficient in hot and dry conditions
Water Use Efficiency	Lower water use efficiency	Higher water use efficiency
Adaptation	Better adapted to cool and temperate climates	Better adapted to warm and tropical climates
Biomass Production	Lower biomass production	Higher biomass production
Mesophyll Cells	More than two between vascular bundles	Two between neighboring vascular bundles
Bundle Sheath Cells	Smaller in size and fewer chloroplasts	Larger in size and more chloroplasts
Dark Reaction Pathway	Calvin cycle	Hatch-Slack pathway
Preferred Climate	Cool and wet environments	Warm and dry environments
Chloroplast Type	Granal type	Granal and agranal types
Carbon Fixation	Once	Twice
Location of Dark Reaction	Mesophyll cells	Mesophyll and bundle sheath cells
Optimum Temperature	Lower	Higher
Photorespiration	Not suppressed	Suppressed
Rate of Carbon Fixation	Slower	Faster
Stomatal Dependence	Require stomata to be open for photosynthesis	Can perform photosynthesis even with closed stomata
Examples	Rice, wheat, soybeans	Corn, sugarcane, sorghum